The present invention relates to game sticks, and more particularly to an improved hollow handle or shaft for hockey sticks used in street hockey, ice hockey, and the like, and which has greater resistance to breaking and cracking than prior art shafts. Hollow shafts of this type may also be used, for example, as exercise wands, lacrosse stick handles, and curling broom handles.
It is well known that hockey sticks are subjected to a variety of stresses during the course of a hockey game, and that it is desirable that the sticks be both durable and flexible to avoid permanent deformation and breakage due to impact. Along this line, it has been suggested that hockey sticks having hollow shafts or handles and made from synthetic materials have desirable durability and flexibility. For example, U.S. Pat. 3,961,790 shows a hollow hockey stick shaft of synthetic material and having a rectangular cross-section in conjunction with a non-integral blade for improved fracture resistance over conventional wooden hockey stick shafts. U.S. Pat. 4,086,115 discloses a hollow, resin impregnated fiberglass shaft of rectangular cross-section using Kevlar rovings or carbon-graphite type fibers for reinforcement and determination of the flexibility of the shaft. In addition, Canadian Pat. No. 918,697 shows a plastic hockey stick having a substantially pyramidally shaped hollow in its shaft providing greater mass at the blade end of the shaft for shock resistance.
Customarily, hockey players prefer hockey stick shafts having substantially rectangular cross-sections. Such a shaft affords the user a comfortable grip in addition to providing him with greater awareness of and control over the orientation of the blade during play, as compared with, for instance, a shaft having a circular or square cross-section. It has been discovered that hockey sticks having hollow shafts of synthetic material with rectangular cross-sections defined by a pair of identical, parallel, planar broad sides connected by a pair of identical, parallel, planar narrow sides, the broad sides and narrow sides having generally the same wall thickness, tend to crack or break when subjected to the normal forces generated during the course of play. This cracking or breaking generally occurs in a corner of the shaft where one broad side meets one narrow side, or in the wall of a narrow side, where stresses are most concentrated.
In order to make such hockey stick shafts more durable it has been found necessary to increase the wall thickness of the sides of the shaft or to provide reinforcing ribs in the interior of the shaft. While this increases the strength of the shaft, it also increases the weight of the shaft and decreases its flexibility. In addition, the increase of material in the shaft renders it more costly.